I have the small book by James E. Williams who put together a listing of Texas units from company level to regimental. It is not 100 per cent complete but still very good.
I have two Galveston Guards units - no regimental affiliation listed (but probably 9th Texas Infantry as they had two with this name according to Tancig). As follows:
Galveston Guards, Co. A - Cpt. RH Howard
Galveston Guards, Co. B - Cpt. Andrew Neill
Williams had no listing for the Wigfall Guards but Tancig has them as unknown company letter, 9th Texas Infantry.